Açıklama :
This scene from the early morning hours
of July 3 looks out across the River Thames from the
Westminster Bridge.
Part of a luminous
timelapse video (vimeo),
the frame captures
a sight familiar in London, the nighttime glow of the London Eye.
But a not-so-familiar
sight is shining in the still dark sky above, widespread
noctilucent
clouds.
From the edge of space, about 80 kilometers above Earth's surface, the
icy clouds
can still reflect sunlight even though the Sun itself is
below the horizon as
seen from the ground.
Usually spotted at
high
latitudes in summer months the diaphanous
apparitions are also known as polar mesospheric clouds.
The seasonal clouds are understood to form as water vapor driven
into the cold upper atmosphere condenses on the fine dust particles
supplied by
disintegrating meteors
or volcanic ash.
NASA's AIM mission provides
daily projections of the noctilucent
clouds as
seen from space.